The present invention broadly relates to a gear-cutting process and pertains, more specifically, to a new and improved apparatus for adjusting the drums of a bevel-gear cutting machine.
Generally speaking, the new and improved construction of apparatus for adjusting the drums of a bevel-gear cutting machine is of the type comprising:
a generating stock having a motor-driven generating drum and a plurality of setting drums, particularly an eccentric drum, an orientation drum and an inclination drum;
clamping devices for clamping one of the setting drums in its desired position at the adjacent setting drum therefor;
reading devices for reading the set or adjusted position of each setting drum;
a cutter head which is rotatably mounted in the setting drums; and
a gear train for driving the cutter head.
A bevel-gear cutting machine contains a rotatably mounted motor-driven generating drum in a generating stock or column in order to produce gear wheels according to the generating method. In this generating drum there is rotatably mounted an eccentric drum. An orientation drum is rotatably mounted in the eccentric drum and, finally, an inclination drum is rotatably mounted in the orientation drum.
A cutter head is rotatably mounted in the inclination drum. The setting drums, i.e. the eccentric drum, the orientation drum and the inclination drum have to be adjusted or set prior to manufacture of a gear wheel such that the cutter head rotatably mounted in these setting drums assumes the desired position for cutting a gear wheel.
In known gear-cutting machines this adjustment of the setting drums is very complicated and only possible with various auxiliary or supplementary means. Since these setting drums, namely the eccentric drum, the orientation drum and the inclination drum are unsymmetrically constructed and since the two setting drums in the front are also eccentrically structured, the mass center of each setting drum is outside or beyond the respective drum axis of rotation and the force of gravity causes a torque to act upon these setting drums.
To avoid having to provide a separate drive for each setting drum, it would be conceivable to rotate the setting drums into the desired position by means of a motor-driven cutter head and by means of a coupling or connection of the setting drum with the cutter head, such setting drum being the drum to be adjusted. For example, it should be possible to connect the cutter head with the inclination drum, release the clamping between the inclination drum and the orientation drum and then very slowly drive the cutter head until the inclination drum reaches the desired position. In order that this process can be automated, the clamping or releasing of each setting drum would have to be automatically effected, for example, by means of a set of springs or a hydraulic drive, and the connection between the cutter head and the inclination drum would have to be accomplished by an electromagnetically actuatable locking device.
Unfortunately, the adjustment of the setting drums in this manner is not feasible because the aforesaid torques are far too large, although these torques which are subject to the action of gravity actually augment or promote rotational motion in certain positions of the setting drums. However, in other positions of the setting drums these torques obstruct rotation. Such torques are of such a magnitude that the gear train for the drive of the cutter head would be seriously damaged.